Lamp.



w.I. BGH/IN.

LAMP.

APPLICATION FILED 0cT.5,I9I1.

1 ,273,994. Patented July 30, 1918.

`of Fig. 1.

WILLIAM J. ROHAN, 0F ST. PAUL, MINNESOTA.

. LAMP.

Specification of Letters Patent.

Application Bled October 5, 1917.A lSerial No. 184,985;

To all whom Ait may concern.'

Be it known that I, WILLIAM J. BOHAN, a citizen of the United States,and resident of St. Paul, county of" Ramsey, and State of Minnesota,have invented certain new and useful Improvements in Lamps, of whichvthe following is a specification, and which are illustrated in theaccompanying drawings, forminga part thereof. l

The invent-ion relates to lamps in which the illuminating agent is `anincandescent bulb, or equivalent device, and in'which the bulb islocated within a projecting reflector.

The object of the invention is to provide improved means for focusingthe bulb with reference to the reflector; and .it consists in astructure such as is hereinafter described and as illustrated in the'accompanying drawings, in which- Figure 1 is a longitudinal sectionthrough the lamp; and 1 Fig. 2 is a sectional view on the line 2-2 Thelamp comprises a casing or shell 10, here shown as bowl shaped andhaving a hollow stem 11 which is externally threaded.

- ranged and equally s The lamp may be supported by any suitable means,such as a bracket-arm '12. secured to the shell. A projecting reflector13 is housed within the shell, and is apertured at its inner end, asshown at 14, to accommodate the base 15 of an incandescent bulb 16. 'lothe base 15 is suitably attached a cap 17 fitting over the stem 11, thisattachment being preferably by means of threaded engagement with atubular stem 18- rojecting inwardly from the cap 17 and) through whichtheleading-in wires 19 may be conveniently entered. `7 The annularflange 20 of the cap 17 issecured to a collar 21 in threaded engagementwith the stem 11 by mea-ns of annularly-arcedadjusting screws 22, 23, 24and 25. e diameter of the annular flange 20 is vsufficiently greaterthan that ofthe collar 21 to permit lateral adjustment of tl e capthrough the agency of the adjusting screws lrews have their inner endsrounded, asy in cated at 26, to engage an annular groove 27 in theperiphery of the collar 21. Jam nuts, as 28. may bc mounted upontbeadjusting screws toengage the outer face of the flange 20.

The described construction provides for the universal adjustment of thebulb 16 with reference to the reflector 13. By turning up ,Patented July30,1918.:

one of a pair ofidiametrically disposed `ad- Justing screws and turningback the other screw of the same pair, the cap 17, and with it the bulb16, may bemoved laterally. The members of the other pair of screws will,of course, be setl up tightly against the collar after such adjustment,in order to securely bindithe parts together. By shifting the collar 2:1upon the stem 11, the capand bulb may be axially adjusted. The twoadjustments, therefore, permit the locating of the bulb at any pointwithin the chamber of the reflector, thereby Securing an accurate focusof the lamp.

Incandescent bulbs lack uniformity of construction, the filament ofwhatever formed, being differently positioned in many instances.Adjustment4 becomes necessary where, as in locomotive headlights, highefficiency is required. -Readjustment is frequently necessary owing to atendency of the filament to sag when heated, as indicated by dottedlines in Fig. 1. v

While a preferred embodiment of the invention is illustrated, various.structural changes may be made withgut departing from its scope.

I cla-im as'my invention- .1. In a projecting lam in combination, ashell having an externally threaded tubular stem, a reflector housedwithin the shell and having an aperture in its inner end, anincandescent bulb located within the reflector, the lbase of the bulbextending through the aperture thereof, a collar in threaded engagementwith the stem of the shell, a cap attached to the base of the b ulb andhaving a, flange surrounding the collar and spaced apart therefrom, andadjusting screws in threaded engagement'with thel flange and bearingupon the collar.

2..In a projecting lamp, in combination, i

a shell having an externally threaded tubular stem, a reflector housedwithin the shell and having an aperture at its inner end, a capoverlapp'ingrthe stem of the shell and having an axially tubular Astementering and of less dia-meter'than' the stem of the shell, -anincandescent bulb located within the reflector and having its'baseattached to the tubular stem of the cap, avcollar in threadedvengagement with the stem of the shell, and

adjusting screws"connecting the cap with-the no lar stem, a reilectorhoused Within the shell and having, an aperture at its inner end, anincandescent bulb located WithinA the reector, the base of the bulbextending through the aperture thereof, a. collar in threaded engagementwith the stem of the shell, and a bulb carrier secured to the collar andbeing lateral-ly adjustable with reference thereto.

4. In a projecting lamp, in combination, a shell having a tubular stein,a reilector housed Within the shell and having an aperture at its innerend, an incandescent bulb located within the reflector, the base of thebulb extending` through the aperture thereof, a collar mounted andaxially adjustable on the stem of the shell, and a bulb carrier securedto the collar and laterally adjustable with reference thereto.

5. In a lamp support, in combination, a tubular stern, a collar threadedupon the stem, and a c ap having a socket for receiving a lamp base andbeing secured to the collar and laterally adjustable with referencethereto.

WILLIAM J. BOHAN.

Copie: ot this patent my be obtained for ve cents each, by addressingthe Commissioner of latents,

' Washington, D. C.

